The invention relates generally to percutaneous spinal implants, and more particularly, to percutaneous spinal implants for implantation, for example, between adjacent spinous processes and optional subsequent removal therefrom.
A back condition that impacts many individuals is spinal stenosis. Spinal stenosis is a progressive narrowing of the spinal canal that causes compression of the spinal cord. Each vertebra in the spinal column has an opening that extends through it. The openings are aligned vertically to form the spinal canal. The spinal cord runs through the spinal canal. As the spinal canal narrows, the spinal cord and nerve roots extending from the spinal cord and between adjacent vertebrae are compressed and may become inflamed. Spinal stenosis can cause pain, weakness, numbness, burning sensations, tingling, and in particularly severe cases, may cause loss of bladder or bowel function, or paralysis. The legs, calves and buttocks are most commonly affected by spinal stenosis, however, the shoulders and arms may also be affected.
Mild cases of spinal stenosis may be treated with rest or restricted activity, non-steroidal anti-inflammatory drugs (e.g., aspirin), corticosteroid injections (epidural steroids), and/or physical therapy. Some patients find that bending forward, sitting or lying down may help relieve the pain. In some cases, bending forward may create more vertebral space, which may temporarily relieve nerve compression. Because spinal stenosis is a progressive disease, the source of pressure is often corrected surgically (e.g., decompressive laminectomy) when the patient has increasing pain over time. Known surgical procedures can remove bone and other tissues that have impinged upon the spinal canal or put pressure on the spinal cord. For example, two adjacent vertebrae can also be fused during the surgical procedure to prevent an area of instability, improper alignment or slippage, such as that caused by spondylolisthesis. Alternatively, decompression can relieve pressure on the spinal cord or spinal nerve by widening the spinal canal to define more space. This procedure requires that the patient be given a general anesthesia because an incision is made in the patient to access the spine to remove the areas that are contributing to the pressure. This procedure, however, may result in blood loss and an increased chance of significant complications, and usually results in an extended hospital stay.
Minimally invasive procedures have been developed to provide access to the space between adjacent spinous processes such that major surgery is not required.
Known medical devices have been developed to be permanently implanted between spinous processes. Such devices, however, can be subject to wear or can cause collateral conditions that would necessitate the removal of the medical device. The removal of the medical device can be difficult to accomplish percutaneously.
Thus, a need exists for improvements in devices and methods for the treatment of spinal conditions such as spinal stenosis.